U. S. Rep. Aaron Schock's surprise announcement Tuesday that he'll resign his seat set off a new round of questions about what happens next for the Peoria Republican, about who might replace him and what it means for his central Illinois district.

Schock, seen as a kind of new GOP face when he was elected in 2008 as the youngest member of Congress, faced a barrage of queries in recent weeks about spending irregularities. The Associated Press confirmed Monday that the Office of Congressional Ethics had apparently begun an investigation.

The 33-year-old said in Tuesday's statement the questions had become a distraction and he will step down at the end of the month.

Here are a few things to know:

WHAT'S NEXT WITH INVESTIGATION

With Schock announcing his resignation for March 31, any investigation by the Office of Congressional Ethics would likely draw quickly to a close at that time and the House Ethics Committee would drop the matter. But that doesn't mean any evidence House investigators have gathered will be discarded.

Investigators could still turn over their findings before then to the Justice Department or the Federal Election Commission.

An FEC investigation would not be affected by whether a politician is in or out of office, said Timothy W. Wright III, a Chicago-based attorney and former chief of staff for Congressman Bobby Rush, a Democrat.

As an example of the interplay between ethics and criminal investigations, Wright noted the House launched an ethics investigation of then-Congressman Jesse Jackson Jr. before his 2012 resignation. A year later, federal authorities charged the Chicago Democrat with illegally spending $750,000 in campaign money for personal expenses.

Jackson pleaded guilty and began serving a 2 1/2-year prison term later in 2013.

Both the primary and the general election must take place within 120 days of the vacancy, meaning voters will select a replacement by the end of July. Until then the seat remains empty.

WHO'S INTERESTED

Several GOP state senators said Tuesday they're interested in representing the heavily Republican 18th district, which includes parts of Peoria, Bloomington and Springfield and stretches to the state's western border.

State Sen. Darin LaHood of Dunlap, who has served in the Senate since 2011, said he'll announce Wednesday whether he'll seek the seat, and Republican officials in Washington said he plans to run. LaHood is the son of former GOP U.S. Rep. Ray LaHood, who preceded Schock in the congressional seat and later served as Transportation Secretary under President Barack Obama.

State Sens. Jason Barickman and Bill Brady, both of Bloomington, also said they're considering running.

Brady, who has served in the Legislature since 1993 and made three unsuccessful bids for governor, said he'll decide by next week. Barickman has been a lawmaker since 2011. He said he'll discuss the idea with his wife and decide soon.

PLAYING BACK HOME

In Peoria on Tuesday, Schock's constituents were struggling to digest the news, with many surprised at how abruptly he resigned.

Barbara O'Dell, who said she watched Schock rise from a school board member to Congress, said she learned of the news via text message.

"I am surprised he resigned because I think he's brazen. People tend to forget, and re-elect these people," she said. "I assumed he would wait it out."

Tyler Beall, a Bradley University student and waiter at a local restaurant, called the situation "kind of sad to see."

"He let his personal life and the stigma of those choices affect his decisions about his professional future," Beall said.

The congressman's office was largely quiet late Tuesday afternoon. Staff members had no comment on Schock's announcement, though one staffing the front desk said he learned of it on TV.